Method and system for a remote wire feeder where standby power and system control are provided via weld cables

ABSTRACT

The present invention is directed to a remotely controlled welding machine that uses serializing and modulating circuits to transfer modulated data packets to a welding power source across a weld cable. A transmitter transmits the data packets of desired welding operational parameters to a receiver disposed in the power source across a weld cable also designed to carry welding power from the power source to the wire feeder. The transmitter and other electronics of the wire feeder are constructed to use only a small amount of power which, preferably, is supplied by a DC power supply external to the wire feeder. The DC power supply is designed to provide power to the electronics of the wire feeder when the wire feeder is in a standby mode of operation.

CROSS REFERENCE TO RELATED CASES

The present application is a continuation of and claims priority of U.S.Ser. No. 10/709,148 filed on Apr. 16, 2004, the disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to welding machines and, moreparticularly, to a method and apparatus of maintaining powering of abattery-less remote device during standby mode of operation. Theinvention further relates to a power source whose operation is governedby control signals provided by a controller in response to data packetsreceived across a weld cable connecting a wire feeder to the powersource.

MIG welding, formerly known as Gas Metal Arc Welding (GMAW), combinesthe techniques and advantages of TIG welding's inert gas shielding witha continuous, consumable wire electrode. An electrical arc is createdbetween the continuous, consumable wire electrode and a workpiece. Assuch, the consumable wire functions as the electrode in the weld circuitas well as the source of filler metal. MIG welding is a relativelysimple process that allows an operator to concentrate on arc control.MIG welding may be used to weld most commercial metals and alloysincluding steel, aluminum, and stainless steel. Moreover, the travelspeed and the deposition rates in MIG welding may be much higher thanthose typically associated with either Gas Tungsten Arc Welding (TIG) orShielded Metal Arc Welding (stick) thereby making MIG welding a moreefficient welding process. Additionally, by continuously feeding theconsumable wire to the weld, electrode changing is minimized and assuch, weld effects caused by interruptions in the welding process arereduced. The MIG welding process also produces very little or no slag,the arc and weld pool are clearly visible during welding, and post-weldclean-up is typically minimized. Another advantage of MIG welding isthat it can be done in most positions which can be an asset formanufacturing and repair work where vertical or overhead welding may berequired.

A wire feeder is operationally connected to the power source and isdesigned to deliver consumable wire to a weld. To further enhance theoperability of the wire feeder of a MIG welding system, known weldingsystems have connected the power source and the wire feeder to oneanother across a dedicated control cable that is in addition to adedicated weld cable such that control signals defining the operationalparameters of the power source are transmitted or fed back from the wirefeeder to the power source, generally referred to as remote control.

One type of remote control device is used to regulate the operationalwelding parameters, and switch the welding power source output ON andOFF as well as change the power source mode via a pendant that connectsto the power source by a multi-conductor cable. The solution isschematically illustrated in FIG. 1A. A wire feeder 2A is connected to apower source 4A by a control cable 6A that includes a 14-pin connector.The cable 6A used to transmit operational information to, and in somecases from the power source, may incorporate 2 to 14 conductorsdepending on how many functions are to be controlled. Separatelyconnected between the power source 4A and wire feeder 2A is a highvoltage weld cable 8A that delivers welding power to the wire feeder andcreates a voltage potential between an electrode and a workpiece.

A significant drawback to this cable-based control is that the controlcable is typically fragile relative to the welding cables designed tocarry high currents at high voltages. Welding machines are commonly usedat construction sites or shipyards where it is not uncommon for thewelding machines to be periodically relocated or surrounded by othermobile heavy equipment operating in the same area. As such, the remotecontrol cable can become damaged by being crushed or snagged fromcontact with surrounding machines and/or traffic. This can cause damageto the wire feeder and/or the welding power source if internal powerconductors become shorted to signal leads that are connected tosensitive signal level circuitry.

One known system is a voltage following or voltage sensed wire feederhaving an internal contactor. This solution is schematically shown inFIG. 1B. As shown, this system includes a wire feeder 2B that receivesits electrical power from the voltage present in the welding circuit.The wire feeder is connected to a power source 4B via a weld cable 8B.One disadvantage of this system is that the operator has no convenientway to adjust the output of the welding power source to compensate forchanges in workpiece thickness and/or fit up. The operator may callanother person more conveniently located to the power source with aradio or some other means of communication to make the adjustment;however, if the operator is working alone, s/he must return to the powersource to make the necessary adjustments. Another disadvantage of thissystem is that it requires the presence of a high current DC contactorto de-energize the welding circuit at the wire feeder. These contactorsare large, heavy, costly, and require periodic maintenance to ensureproper and continual operation. The location of the secondary contactorin the remotely located wire feeder also requires that the weldingcircuit from the welding power source to the wire feeder remainenergized even when not welding so that power is available to the wirefeeder and welding arc when the gun trigger is activated. Accordingly,an open circuit voltage remains present across the weld cables. The weldcables, however, can become damaged at a worksite resulting in anunwanted arc being formed between an exposed portion of the cable and anunexpectant ground.

Another remote control solution is described in U.S. Ser. No.10/604,482, which is assigned to the Assignee of the presentapplication. Notwithstanding the numerous advancements achieved with theinvention of the aforementioned pending application, such a systemrelies upon pulse width modulation to remotely transmit operational datafrom a wire feeder to a power source across a weld cable. By using pulsewidth modulated signals to remotely control operation of a power source,the amount of data as well as variability in the types of data thatcould be transmitted between the wire feeder and a power source islimited when compared to that which may be achieved with encoded datapackets communications. This data packet also allows for error checkingwhich improves robustness and reliability of the control. Further, withthe system described in the aforementioned pending application, the wirefeeder requires an internal DC power supply to power the electronics ofthe wire feeder. That is, the invention of the above-referencedapplication teaches the avoidance of an open circuit voltage between thewire feeder and power source. As a result, absent a DC power supply, thewire feeder cannot be minimally powered so as to communicate with thepower source to initiate the welding process.

It is therefore desirable to design a remote controlled welding machinethat receives encoded data packet command signals from a wire feederacross a weld cable to control or otherwise regulate operation of apower source. It would also be desirable to design a remote controlledwelding system without needing a dedicated DC power supply disposed in awire feeder. It would be further desirable to design a wire feeder thatreceives a low voltage DC input to maintain powering of wire feederelectronics when the wire feeder is in a non-welding, standby mode viaonly the weld cable connections.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to a remotely controlled weldingmachine that overcomes the aforementioned drawbacks. A remote controluses serializing and modulating circuits to transfer serialized andmodulated data packets to a welding power source across a weld cable.The information to be communicated to the power source includes weldingpower source output command information (amperage/voltage control),welding circuit on/off information (power source output contactorcontrol), and power source mode control (constant voltage/constantcurrent). A transceiver transmits the data packets of desired weldingoperational parameters to a receiver disposed in the power source acrossa weld cable also designed to carry welding power from the power sourceto the wire feeder. The transceiver and other electronics of the wirefeeder are constructed to use only a small amount of power which,preferably, is supplied by a DC power supply external to the wirefeeder. The DC power supply is designed to provide power to theelectronics of the wire feeder when the wire feeder is in a standby modeof operation. The power source includes a decoder to decode the datapacket and input the decoded data to a controller for dynamic control ofthe power source.

Therefore, in accordance with one aspect of the present invention, awelding system is provided and includes a power source having a primarycontactor and a secondary contactor. The welding system further includesa weld cable connecting the power source to a remote device. The remotedevice is operable in a standby mode. The welding system furtherincludes a controller to regulate activation of the first and the secondcontactors such that a non-welding voltage is applied from the powersource to the remote device across the weld cable when the remote deviceis in a standby mode.

In accordance with another aspect of the present invention, a weldingsystem includes a power source configured to supply a first power usableduring a welding process and supply a second power during a standby modeof operation. The welding system further includes a wire feederconfigured to receive the first power from the power source whensupplying a consumable electrode to the weld and receive the secondpower when in the standby mode of operation. A welding cable is providedand connects the power source and the wire feeder to one another, and isconfigured to carry the first and second powers thereacross.

According to another aspect of the present invention, a method ofremotely controlling a power source for welding is provided. The methodincludes the step of packaging feedback of operational commands for awelding-type process into a data packet of encoded data. The methodfurther includes the step of transmitting the data packet to a powersource from a remote device across a weld cable designed to providewelding power for the welding-type process. The power source iscontrolled in accordance with at least data embodied in the data packet.

Various other features, objects and advantages of the present inventionwill be made apparent from the following detailed description and thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate one preferred embodiment presently contemplatedfor carrying out the invention.

In the drawings:

FIGS. 1A-1B are schematic block diagrams illustrating examples of knownremotely controlled welding and wire feeder systems.

FIG. 2 is a pictorial view of a welding system in accordance with oneaspect of the present invention.

FIG. 3 is a schematic of the welding system illustrated in FIG. 2.

FIG. 4 is a schematic diagram of a single data packet transmittablebetween a wire feeder and a power source in accordance with one aspectof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be described with respect to regulation of apower source and a battery-less wire feeder of a MIG welding systembased on modulated feedback provided from a transceiver remote from thepower source to a receiver incorporated within the power source.However, the present invention is equivalently applicable withregulating power sources of TIG, stick, flux cored, and the like weldingsystems. Moreover, the present invention is also applicable withnon-welding, high power systems such as plasma cutters and inductionheaters.

Referring to FIGS. 2 and 3, a MIG welding system 10 includes a weldingpower source 12 designed to supply power to a wire feeder 14 through aweld cable 16. The power source is designed to run in one of a number ofmodes including constant voltage (CV) and constant current (CC). Alsoconnected to the power source is a secondary work weld cable 18 thatconnects the power source to a clamp 20 designed to receive cable 18 toworkpiece 22. Also connected to wire feeder 14 is a welding gun or torch24 configured to supply consumable welding wire to a weld. Weldingsystem 10 may further include a gas cylinder 26 connected to wire feeder14 such that shielding gas can be provided through gas hose 28 for theMIG welding process.

Power source 12 is designed to condition raw power supplied from autility line or engine driven power supply and output power usable bythe welding process. As such, power source 12 includes one or moretransformer assemblies (not shown) to condition the raw power. Theoutput of the power source is generally controlled by a controller andassociated operational circuitry that regulates the secondary or outputside of the power conditioning components. As such, the power source maybe initially powered but not provide a welding output until thesecondary power circuit is energized through the closing of a highcurrent DC contactor or other switching assembly. As will be describedin greater detail below, power source 12 is regulated such that asecondary or welding power output is not provided until gun 24 isactivated signaling commencement of the welding process. In this regard,a welding circuit is not created between power source 12 and workpiece22 until gun 24 is activated and is placed in relative proximity withworkpiece 22.

Torch 24 is equipped with a pushbutton trigger 30 that when depressedcauses a transceiver 32 of a controller 34 within wire feeder 14 totransmit command signals to a receiver 36 and power source 12 throughweld cable 16. As such, a separate control cord connecting the wirefeeder and power source to one another is avoided. Further, as will bedescribed in greater detail below, wire feeder 14 is preferablyconstructed without a contactor assembly to close the welding circuit.That is, the power necessary for the wire feeder 14 to supply wire tothe weld is not always present across weld cables 16 and 18.Accordingly, a separate contactor or switch assembly is not needed inwire feeder 14 to close the welding circuit. The customary open circuitwelding voltage between a power source and a wire feeder is theneliminated because a transceiver disposed within the wire feedertransmits command signals through weld cables 16 and 18 to a receiver 36disposed within the power source that is designed to communicate with acontroller 38 of the power source such that secondary or a welding poweroutput is not provided until the command signal is received from thetransmitter 32 in the wire feeder.

This construction has a number of advantages. First, the wire feeder 14is designed to be a portable or “suitcase” wire feeder such thatreduction in weight is clearly advantageous. As such, constructing wirefeeder 14 to operate without a separate contactor assembly reduces theoverall weight and size of the wire feeder. Furthermore, the contactorsrequired for high current DC applications can be quite expensive therebyincreasing the overall cost of the wire feeder. Additionally, thecontactor assembly is a maintenance item that may require routinemaintenance for continued proper operation. Therefore, constructing wirefeeder 14 without such a contactor assembly has a number of size- andcost-associated advantages.

Second, incorporation of a transceiver within wire feeder 14 thatcommunicates with a transceiver in power source 12 directly through weldcables 16 and 18 eliminates the need for a separate control/power cable.The control cable adds to the complexity, weight, and overall cost ofthe welding system. Additionally, as previously noted, the control cordis typically less durable than the welding cables and, as such, is proneto nicks and snags typically associated with industrial locations.Moreover, incorporating the wire feeder without a separate contactorimproves the overall current capacity of the wire feeder. That is, therating of the contactor assembly within the wire feeder generallydictates the ampacity loads of the wire feeder. Removal of the contactorassembly thereby allows the ampacity loads to be governed by othercomponents of the wire feeder which typically have greater maximumampacity loads than the contactor assembly.

This invention includes at least a pair of transceivers: one in thepower source and one in the wire feeder. In this regard, bi-directionalcommunication is supported between the wire feeder and the power source.It is contemplated, however, that the wire feeder may be equipped with atransmitter and the power source with a receiver to supportuni-directional communication between the two components. Thetransceiver in the wire feeder is designed to transmit serialized andmodulated packets of feedback or commands to a transceiver in the powersource across the weld cable. In one embodiment, the wire feederoperates in an on-demand fashion and, as such, when the trigger isdepressed or otherwise activated, a command signal is transmitted acrossthe weld cable to the power source that is responsive thereto anddelivers welding power to the weld. This application of power, i.e.closing of the welding circuit, causes the wire feeder to deliverwelding wire to the weld. As will be described more fully, the wirefeeder transceiver is designed to transmit a data packet that includesinformation in addition to the startup command initially presented whenthe trigger is depressed.

The signal includes information regarding desired operational parametersof the wire feeder and instructs the transceiver of the power source toset the magnitude of the output of the welding power source (volts oramperes), the mode of the welding power source (CC or CV), and wire feedspeed among other parameters. The transmitter is also configured totransmit commands regarding JOG and PURGE functions. That is, when theJOG button is pushed on the wire feeder, the transmitter automaticallyrepeats the minimum reference command each time the open circuit voltageof the welding power source falls to zero. In accordance with known wirefeeder construction, the operator may select operational parameters on auser panel of the wire feeder. In a further embodiment, the user panelmay be integrated with the electrode holder or torch to allow usercontrol of the welding process without leaving the weld.

Referring again to FIG. 3, the welding system 10 is designed to provideserialized and modulated communication between the wire feeder 14 andpower source 12. In this regard, controller 34 of wire feeder 14 alsoincludes an encoder 40, serializing circuitry 42, and modulator 43.Serializing circuitry 42 is designed to serialize communications betweenthe wire feeder and the power source based on user input to a user panel44 and for feedback provided from the weld. Encoder 40, as will bedescribed with respect to FIG. 4, is designed to encode the serializedtransmission into data packets for improved and more efficienttransmission to the power source 12. Modulation 43 is designed tomodulate the data packets before transmission. A number of transmissiontechniques is envisioned including, but not limited to spread spectrumand pseudo-random sequenced using amplitude and/or phase-shifting.Spread spectrum technology is a method of communication that istypically implemented to secure communications and/or to overcomenarrow-band constraints of a transmission line, i.e. a weld-cable.

As described above, user panel 44 is designed to receive discrete inputsfrom an operator that collectively define operation of a weldingprocess. As wire feeder 14 supports digitized control of the weldingprocess, the operator is able to input with a certain degree ofspecificity exact operating parameters via user panel 44. However, aswelding system 10 is a remotely controlled system, controller 34 of wirefeeder 14 receives the user inputs whereupon those inputs are fed toserializing circuit 42 to arrange the user input data into data packetsthat support streamlined communication of the control commands across asingle transmission—weld cable 16.

Power source 12 also includes a decoder 46 and demodulator 47 that arematched with the encoder 40 of the wire feeder so as to demodulate anddecipher the encoded signal received from transmitter 32 across weldcable 16. Based on the deciphered commands, controller 38 will regulateoperation of power source 12 in accordance with the user inputs to thewire feeder 14. One skilled in the art will appreciate thatcommunication between the power source and wire feeder may occur duringwelding or in stand-by. As will be described with respect to FIG. 4,decoder 46 is able to verify the accuracy of the transmitted data basedon the particular encoding used.

Referring now to FIG. 4, a portion of an encoded transmission or datapacket in accordance with the present invention is shown. Transmission48 is encoded into a single data packet to include address data 50,operational control data 52, and package checksum data 54. A data packetcomprises multiple bits, bytes, or words of data. Based on theconfiguration or encoding of this transmission, decoder 46 is able tonot only receive a well-ordered transmission, but also verify theaccuracy of the transmitted data by checksum 54. A checksum is an errordetection mechanism having a form of a numerical value based on thenumber of bits or bytes in the transmitted message. In this regard,decoder 46 is able to apply a formula or algorithm used to generate thechecksum value to the received message and verify that the accompaniednumerical value is the same. In this regard, controller 38 of the powersource can assume if the checksums do not match that the transmittedmessage or signal has been garbled and therefore should be ignored.Simply put, if the controller 38 based on information provided bydecoder 46 determines a checksum value of the transmission that matchesthe checksum value 54 embedded in the transmission, the transmission isdeemed to be correct and should therefore be processed accordingly.

As mentioned above, each packet comprises three sections: a preamble,the packet body, and a checksum or Cyclical Redundancy Check (CRC).Encoding of the preamble may be achieved through Amplitude Shift Keying(ASK). ASK uses alternating SUPERIOR and INFERIOR states to encodesymbols. Based on the encoded pattern or states, the controller of thepower source is able to properly control power output to the wirefeeder. In this regard, the encoding of the preamble may be used toindicate which parameter the data of the packet body pertains. Todistinguish the preamble from the packet body, another modulation schememay be used. For example, Phase Reversal Keying (PRK) may be used toencode the packet body. PRK uses two phases of the SUPERIOR state whichare, in one embodiment, 180 degrees out-of-phase from one another toencode the data. PRK is generally considered more robust than ASK. TheCRC code at the end of the packet is used to improve the reliability ofthe communications link.

Referring again to FIG. 3, welding power source 12 may include a lowvoltage DC power source 56 that is used as a secondary source of voltagethat may be applied across weld cable 16 when the battery-less wirefeeder 14 is in an ON, but non-welding mode, i.e. standby. In thisregard, the electronics to the wire feeder 14 are sufficiently poweredthereby avoiding a “rebooting” of the wire feeder 14 between weldingprojects. One skilled in the art will appreciate, however, that after aspecified time has elapsed since welding, the wire feeder 14 may beplaced in shutdown.

As mentioned above, low voltage power source 56, which may beincorporated within power source 12 or the external to the power source,is designed to provide a relatively low voltage power supply to the wirefeeder during standby operation of the wire feeder. In a preferredembodiment, the low voltage supply is provided across the weld cable. Assuch, when the low voltage source 56 is integrally disposed within thepower source 12, the power source will include a primary contactor,generally referenced as diode 58, as well as secondary contactor,generally referenced as diode 60, to control the flow of power betweenitself and the wire feeder. That is, a primary contactor 58 iselectrically connected to power conditioner 62, i.e. transformer, whichis designed to condition an input power from a utility or engine drivenpower supply into a form usable by a welding-type process, will be usedto control application of a welding (or relatively high) voltage betweenthe wire feeder and the power source. In this regard, the primarycontactor 58 is not closed so as to form a welding circuit between thewire feeder and the power source until specifically instructed to do soby operator commands received across weld cable 16 from the remote wirefeeder 14. On the other hand, the secondary contactor 60 which iselectrically isolated from primary contactor 58 and is electricallyconnected to low voltage source 56, is used to control application of alow voltage power supply 56. That is, if the power source 12 isoperating and connected to wire feeder 14 or some other periphery, a lowvoltage will be present across cable 16 to power electronics of the wirefeeder or other peripheral device. During the welding process, however,the primary voltage, or a weld voltage, will be used or otherwise“tapped” into by the wire feeder to control its electronics. It isenvisioned that the wire feeder has at least three states—an OFF state,a welding (ON) state, and a standby state. Standby may be defined as anon-welding, ON state wherein the wire feeder and its electronics areenergized but an active welding process is not taking place. It isdesirable to put the wire feeder in standby during intervals betweenwelding.

The voltage sensing receiver section of the remote control is configuredto detect both start and reference commands from the transmitter throughthe weld cable. The receiver switches ON the welding power output of thepower source and sets the magnitude of the power source output. Thereceiver includes a current sensing circuit that detects arc current andmaintains the power source in an ON state while welding. The weldingpower output effectively squashes the standby power output provided topower the wire feeder when in a standby mode. That is, the primary andthe secondary contactor in the power source are in a conductive statewhen welding but only the secondary contactor is conductive when thewire feeder is in standby. In this regard, the wire feeder includescircuitry to effectively “tap” into the weld voltage for powering of itselectronics during welding.

As stated above, the present invention is also applicable with non-MIGwelding systems such as TIG and stick welders. Further, theaforedescribed circuitry may be implemented to automatically adjust theoutput of a power source to compensate for losses that occur across weldcables. That is, in some manufacturing and/or industrial settings, theweld is a relatively great distance from the power source. As such, theweld cables may be dozens to over a hundred feet in length. This weldcable length results in losses from the output terminal of the powersource to the weld. Simply, the voltage at the output terminals of thepower source (where the weld cable is connected to the power source) maybe significantly more than the voltage across the weld. Accordingly, thepresent invention may be used to transmit a voltage feedback signal atthe weld to the power source whereupon a controller in the power sourcecompares the voltage at the terminal to the voltage at the weld andadjusts the voltage at the terminal such that after the lossesexperienced across the weld cables, the voltage at the weld is at thelevel requested by the user.

Therefore, in accordance with one embodiment of the present invention, awelding system is provided and includes a power source having a primarycontactor and a secondary contactor. The welding system further includesa weld cable connecting the power source to a remote device. The remotedevice is operable in a standby mode. The welding system furtherincludes a controller to regulate activation of the first and the secondcontactors such that a non-welding voltage is applied from the powersource to the remote device across the weld cable when the remote deviceis in a standby mode.

In accordance with another embodiment of the present invention, awelding system includes a power source configured to supply a firstpower usable during a welding process and supply a second power during astandby mode of operation. The welding system further includes a wirefeeder configured to receive the first power from the power source whensupplying a consumable electrode to the weld and receive the secondarypower when in the standby mode of operation. A welding cable is providedand connects the power source and the wire feeder to one another, and isconfigured to carry the first and second powers thereacross.

According to another embodiment of the present invention, a method ofremotely controlling a power source for welding is provided. The methodincludes the step of packaging feedback of operational commands for awelding-type process into a data packet of encoded data. The methodfurther includes the step of transmitting the data packet to a powersource from a remote device across a weld cable designed to providewelding power for the welding-type process. The power source iscontrolled in accordance with at least data embodied in the data packet.

The present invention has been described in terms of the preferredembodiment, and it is recognized that equivalents, alternatives, andmodifications, aside from those expressly stated, are possible andwithin the scope of the appending claims.

1.-20. (canceled)
 21. A welding power source comprising: powerconditioning circuitry configured to condition input power into outputpower suitable for use in a welding operation performed by a weldingtorch operationally connected to a welding wire feeder, wherein thewelding power source is configured to deliver the output power to thewelding wire feeder via a weld cable operationally connecting thewelding power source to the welding wire feeder; and control circuitryconfigured to receive command signals from the welding wire feeder viathe weld cable, and to regulate operation of the power conditioningcircuitry based at least in part on the received command signals. 22.The welding power source of claim 21, wherein the command signalsreceived from the welding wire feeder are indicative of a desiredwelding operation.
 23. The welding power source of claim 21, wherein thecommand signals relate to a detected activation of a trigger of awelding torch operationally connected to the welding wire feeder. 24.The welding power source of claim 21, wherein the control circuitrycomprises a receiver configured to receive the command signals, and toregulate the operation of the power conditioning circuitry according todata embodied in the command signals.
 25. The welding power source ofclaim 24, wherein the control circuitry comprises a demodulatorconfigured to demodulate and decipher data packets encoded onto thecommand signals.
 26. The welding power source of claim 25, wherein thecontrol circuitry comprises a decoder configured to decode operationalparameters from the data packets.
 27. The welding power source of claim26, wherein the operational parameters include at least one of amagnitude of the output power, a welding mode, a purging function, and ajogging function.
 28. The welding power source of claim 21, comprising alow voltage power source disposed configured to supply low voltage powersource to the welding wire feeder when the welding wire feeder is in astandby mode of operation.
 29. The welding power source of claim 28,wherein the low voltage power source comprises a DC battery.
 30. Thewelding power source of claim 21, wherein the control circuitry isconfigured to receive the command signals from the welding wire feederwhen the welding power source is delivering the output power to thewelding wire feeder.
 31. A welding wire feeder comprising: controlcircuitry configured to transmit command signals to a welding powersource via a weld cable configured to deliver welding power from thewelding power source, wherein the welding power is suitable for use in awelding operation performed by a welding torch operationally connectedto the welding wire feeder.
 32. The welding wire feeder of claim 31,wherein the command signals transmitted to the welding power source areindicative of a desired welding operation.
 33. The welding wire feederof claim 31, wherein the command signals transmitted to the weldingpower source relate to a detected activation of a trigger of the weldingtorch.
 34. The welding wire feeder of claim 31, wherein the controlcircuitry comprises a transceiver configured to transmit the commandsignals to the welding power source.
 35. The welding wire feeder ofclaim 34, wherein the control circuitry comprises serializing circuitryconfigured to serialize data packets onto the command signals.
 36. Thewelding wire feeder of claim 35, wherein the control circuitry comprisesan encoder configured to encode the serialized data packets withoperational parameters of the welding power source.
 37. The welding wirefeeder of claim 35, wherein the control circuitry comprises a modulatorconfigured to modulate a power characteristic of a power signal on theweld cable to encode the data packets onto the power signal.
 38. Thewelding wire feeder of claim 37, wherein the modulation comprises atleast one of spread-spectrum transmission, pseudo-random sequencing,phase-reversal-keying, and amplitude-shift-keying.
 39. The welding wirefeeder of claim 31, wherein the welding wire feeder is a contactorlesswelding wire feeder.
 40. The welding wire feeder of claim 31, whereinthe control circuitry is configured to transmit the command signals whenthe welding power source is delivering the welding power to the weldingwire feeder.